Mild drying and calcining system and method for thin-wall hollow silicon oxide microspheres

Abstract

The invention discloses a mild drying and calcining system and method for thin-wall hollow silicon oxide microspheres, and belongs to the field of advanced inorganic material preparation. The system is provided with at least one built-in functional assembly in the axial direction of the barrel. A plurality of shoveling plates internally provided with functional components are arranged on the inner wall of the cylinder body in an annular array manner; the air distribution plate is arranged in the center of the radial section of the barrel; the at least two brackets are arranged between the air distribution plate and the inner wall of the barrel body in an annular array manner; the driving mechanism is connected with the roller first end through the transmission mechanism; the hot air generator is communicated with the roller air inlet through a hot air input pipe; the first end of the discharging pipe is rotationally connected with the discharging opening, and the roller rotates at a low speed relative to the discharging pipe; the second end of the discharge pipe is communicated with the cyclone separator; the cyclone separator is communicated with the vibration dispersion sieving mechanism; the vibration dispersion sieving mechanism is communicated with the screw conveyer; and the spiral conveyer is communicated with the calcining furnace. Damage of the fragile hollow structure can be reduced in the drying, calcining and dispersing stages, hard agglomeration is completely eradicated, and industrial production of tonnage or above is achieved.

Description

Technical Field

[0001] This application relates to the field of advanced inorganic material preparation technology, and in particular to a mild drying and calcination system and method for thin-walled hollow silica microspheres. Background Technology

[0002] Thin-walled hollow silica microspheres, with their unique nanometer to submicron-level wall thickness structure, demonstrate irreplaceable value in high-end applications such as advanced drug delivery systems, high-performance catalyst supports, precision microreactors, and next-generation thermal insulation materials. These microspheres are typically prepared using template methods (such as emulsion templates or polymer templates), with the precursor being a wet gel state, resulting in an extremely fragile structure. However, the post-processing stage requires transforming the wet gel into a dry, robust, and well-dispersed final product. This process faces significant technical challenges, particularly in protecting the thin-walled hollow structure from damage at industrial-scale production, which has become a core bottleneck restricting their widespread application.

[0003] Currently, the mainstream drying technologies in industry include spray drying, static drying (such as ovens or tunnel kilns), and freeze drying. Spray drying relies on high-speed rotating atomizing discs (often reaching 10,000 rpm to 30,000 rpm) or high-pressure nozzles to achieve atomization and drying, and has high efficiency. Static drying uses ovens, tunnel kilns, etc., to complete drying through solvent evaporation. Freeze drying utilizes supercritical or low-temperature freezing conditions to avoid the influence of capillary forces. Although these technologies are mature in general material processing, they all have significant limitations when it comes to the special requirements of thin-walled hollow silica microspheres, and cannot meet the requirements of structural integrity and large-scale production.

[0004] The high shear forces generated during spray drying easily tear or crush the already formed but low-strength wet gel hollow spheres. Even if they are not completely crushed, the resulting microcracks will propagate during subsequent treatments such as calcination, leading to product strength far below theoretical values ​​and yields often less than 50%. Thus, spray drying faces the dilemma of "shear damage." Although static drying avoids shear damage, the enormous capillary forces caused by solvent evaporation can cause strong chemical bonds (hard agglomeration) between particles, forming hard lumps that are extremely difficult to disperse. Any subsequent mechanical crushing (such as grinding) will irreversibly damage the hollow structure itself, and the particle size distribution will become uncontrolled. While freeze drying can avoid capillary and shear forces, it requires huge equipment investment (e.g., a medium-sized laboratory freeze dryer can cost hundreds of thousands of yuan), consumes a lot of energy, has a long cycle (often several days), and has limited processing capacity, making it impossible to achieve industrial-scale production of tons or more. Summary of the Invention

[0005] This application provides a mild drying and calcination system and method for thin-walled hollow silica microspheres, which solves the problem that existing thin-walled hollow silica microsphere drying technologies produce high shear forces that easily tear or crush the formed but low-strength wet gel hollow spheres, which are prone to hard agglomeration and cannot achieve industrial production at the ton level or above.

[0006] To achieve the above objectives, the technical solution of this invention is as follows:

[0007] In a first aspect, embodiments of the present invention provide a mild drying and calcination system for thin-walled hollow silica microspheres, characterized in that it includes a drive mechanism, a transmission mechanism, a drum, a hot air generator, a hot air input pipe, a discharge pipe, a cyclone separator, a vibrating dispersion and sieving mechanism, a screw conveyor, and a calcination furnace;

[0008] The drum includes a cylinder and internal functional components;

[0009] The cylinder has a feed inlet on its side wall, an air inlet on its first end face, and a discharge outlet on its second end face.

[0010] At least one of the internal functional components is provided along the axial direction of the cylinder;

[0011] The built-in functional components include a reading board, a bracket, and a wind distribution plate;

[0012] The lifting plates include multiple plates, which are arranged in a ring array around the axis of the cylinder on the inner wall of the cylinder.

[0013] The air distribution plate is located at the center of the radial section of the cylinder, directly opposite the air inlet, and is used to disperse the hot air into a uniform airflow.

[0014] The bracket includes at least two, with the first ends of the at least two brackets arranged in a ring array on the outer wall of the air distribution plate and the second ends arranged on the inner wall of the cylinder;

[0015] The drive mechanism is connected to the first end of the drum via the transmission mechanism;

[0016] The hot air generator is connected to the air inlet of the drum through the hot air input pipe;

[0017] The first end of the discharge pipe is rotatably connected to the discharge port, and the roller rotates at a low speed relative to the discharge pipe under the drive of the drive mechanism.

[0018] The second end of the discharge pipe is connected to the inlet of the cyclone separator;

[0019] The output port of the cyclone separator is connected to the input port of the vibrating dispersion and screening mechanism;

[0020] The output port of the vibrating dispersion screening mechanism is connected to the input port of the screw conveyor;

[0021] The output port of the screw conveyor is connected to the input port of the calcining furnace.

[0022] In conjunction with the first aspect, in one possible implementation, the air distribution plate has multiple through holes evenly distributed, or the air distribution plate has multiple slender slits arranged in parallel.

[0023] In conjunction with the first aspect, in one possible implementation, the mild drying and calcination system for thin-walled hollow silica microspheres also includes an exhaust gas treatment mechanism;

[0024] The exhaust gas treatment mechanism is located on top of the cyclone separator.

[0025] In conjunction with the first aspect, in one possible implementation, the vibration dispersion sieving mechanism includes a sieve chamber, a sieve screen, and a vibration mechanism;

[0026] The inlet at the top of the sieve chamber is connected to the outlet of the cyclone separator, and the sieve screen is installed at the bottom.

[0027] The vibration mechanism is connected to the screen and is used to drive the screen to vibrate;

[0028] The inner cavity of the sieve chamber located below the sieve mesh is truncated.

[0029] The output port of the screen chamber is connected to the input port of the screw conveyor.

[0030] In conjunction with the first aspect, in one possible implementation, the vibration dispersion sieving mechanism further includes sound-insulating cotton;

[0031] The sound insulation cotton is disposed on the outer wall of the sieve chamber located below the sieve mesh.

[0032] Secondly, embodiments of the present invention provide a mild drying and calcination method for thin-walled hollow silica microspheres, based on the aforementioned mild drying and calcination system for thin-walled hollow silica microspheres, comprising:

[0033] Step 1: A thin-walled hollow silica precursor slurry with a solid content of 5% to 25% is fed into the drum through a feed port provided on the side wall of the drum body. The drum rotates at a low speed relative to the discharge port under the drive mechanism.

[0034] Step 2: The thin-walled hollow silica precursor slurry is repeatedly lifted to a certain height by multiple lifting plates arranged in a ring around the axis of the cylinder on the inner wall of the cylinder. Then, the thin-walled hollow silica precursor slurry is freely sprinkled by gravity to form a uniform and continuous thin-layer dynamic material curtain. At the same time, a hot air generator introduces low-temperature hot air at a temperature of 60℃~180℃ into the drum through a hot air input pipe and the air inlet of the drum. The low-temperature hot air is evenly distributed by an air distribution plate set at the center of the radial section of the cylinder and facing the air inlet. It then makes full and gentle contact mass transfer with the thin-layer dynamic material curtain to obtain precursor microspheres.

[0035] Step 3: The precursor microspheres are driven by airflow from the outlet of the cylinder to the outlet pipe, and then transported to the cyclone separator through the outlet of the outlet pipe. In the cyclone separator, gas-solid separation is carried out to obtain solid microspheres.

[0036] Step 4: The solid microspheres are conveyed to the vibration dispersion and sieving mechanism through the output port of the cyclone separator. They are gently dispersed under the adjustable low-frequency and low-amplitude vibration of the vibration dispersion and sieving mechanism to obtain monodisperse precursor microspheres, which are then output to the output port of the vibration dispersion and sieving mechanism.

[0037] Step 5: The monodisperse precursor microspheres are conveyed to the screw conveyor through the output port of the vibrating dispersion sieving mechanism, and then conveyed to the calcining furnace through the screw conveyor in a closed manner. Under air atmosphere, the temperature is slowly increased to 300℃~800℃ at a heating rate of 1℃ / min~5℃ / min for calcination, and held for 1h~8h to obtain hollow silica microspheres.

[0038] In conjunction with the second aspect, in one possible implementation, the rotational speed of the low-speed drum in step 1 is 5 rpm to 25 rpm.

[0039] In conjunction with the second aspect, in one possible implementation, step 3 further includes processing and collecting the separated exhaust gas through an exhaust gas treatment mechanism.

[0040] In conjunction with the second aspect, in one possible implementation, step 4 specifically includes: the solid microspheres being conveyed to the sieve chamber through the output port of the cyclone separator;

[0041] The vibration mechanism drives the screen to vibrate at an adjustable low frequency and low amplitude. The screen gently disperses the solid microspheres to obtain the monodisperse precursor microspheres.

[0042] The monodisperse precursor microspheres are collected through the sieve chamber's platform-shaped inner cavity and then discharged to the sieve chamber's outlet.

[0043] In conjunction with the second aspect, in one possible implementation, the vibration frequency of the vibration mechanism is 15Hz~40Hz, the amplitude is 0.5mm~2mm, and the mesh size of the screen is 200 mesh~2000 mesh.

[0044] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0045] The mild drying and calcination system for thin-walled hollow silica microspheres provided in this application embodiment involves a drive mechanism connected to the first end of a drum via a transmission mechanism upon system startup. The drive mechanism drives the drum to rotate at a low speed relative to the discharge pipe. The thin-walled hollow silica precursor slurry is fed in through an inlet located on the side wall of the drum. Inside the drum, a ring-shaped array of lifting plates repeatedly lifts the slurry to a high position, where it falls freely under gravity, forming a continuous, thin, dynamic material curtain. This process completely avoids high-speed shear forces because the gravity dispersion force is far below the mechanical strength threshold of the wet gel, thus greatly reducing damage to the fragile hollow structure during the drying, calcination, and dispersion stages. Simultaneously, a hot air generator introduces low-temperature hot air (60°C to 180°C) into the drum's air inlet through a hot air input pipe. The hot air is evenly dispersed into a gentle airflow by a distribution plate located radially at the center of the drum, allowing for thorough and gentle heat exchange with the thin, dynamic material curtain, achieving low-temperature, uniform mass transfer drying. This synergistic mechanism completely eliminates the local drying stress in thin-walled hollow silica precursor slurry caused by excessively high local wind speeds or uneven temperatures. Furthermore, because the material is continuously and dynamically updated, there is no opportunity for static bonding between particles, thus eliminating the formation of hard agglomerates at the source.

[0046] After drying, the precursor microspheres are carried by airflow from the outlet into the discharge pipe, and then conveyed to a cyclone separator for gas-solid separation. The resulting solid microspheres then enter a vibrating dispersion and sieving mechanism. This mechanism uses gentle, low-frequency, low-amplitude vibration to dissolve soft agglomerates while simultaneously removing broken particles, outputting monodisperse precursor microspheres. These monodisperse precursor microspheres are then conveyed in a closed spiral conveyor to a calcination furnace, where they are calcined and solidified at a slow heating rate of 1℃ / min to 5℃ / min. Throughout the process, the "gravity-driven dispersion + uniform airflow from the air distribution plate" design of the drum replaces highly destructive atomization; the low-frequency, gentle vibration of the vibrating screen avoids secondary structural damage; and the airtightness of the spiral conveyor ensures contamination-free transmission, ultimately achieving a balance between the structural integrity and dispersibility of the microspheres. The integrity rate of the hollow silica microspheres has increased from less than 50% in traditional spray drying to over 95%.

[0047] This system achieves a balance between "gentle processing" and "continuous production" through the innovative integration of standardized industrial equipment. The drive mechanism, hot air generator, cyclone separator, screw conveyor, and calcining furnace are all mature chemical equipment, significantly reducing the enormous investment costs of specialized equipment (such as freeze dryers). The low-speed roller and air distribution plate work together to achieve low-energy dynamic drying, the low-frequency operation of the screen reduces energy consumption, and the screw conveyor ensures continuous, closed-loop transmission. This allows the system to be easily scaled up to ton-level capacity, possessing extremely high practicality and industrial value, and is readily achievable for large-scale industrial production. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 Schematic diagram of the structure of the mild drying and calcination system for thin-walled hollow silica microspheres provided in the embodiments of this application. Figure 1 ;

[0050] Figure 2 Schematic diagram of the structure of the mild drying and calcination system for thin-walled hollow silica microspheres provided in the embodiments of this application. Figure 2 ;

[0051] Figure 3 Scanning electron microscope (SEM) image of hollow silica microspheres prepared in Example 2 provided for the present application.

[0052] Icons: 1-Drive mechanism; 2-Transmission mechanism; 3-Drum; 31-Cylinder body; 32-Feed inlet; 33-Air inlet; 34-Discharge outlet; 35-Internal functional components; 351-Lifting plate; 352-Support; 353-Air distribution plate; 36-Insulation layer; 4-Hot air generator; 5-Hot air input pipe; 6-Discharge pipe; 7-Cyclone separator; 8-Vibrating dispersion sieving mechanism; 81-Screw box; 82-Screw; 83-Sound insulation cotton; 9-Screw conveyor; A-Calcination furnace; B-Tail gas treatment mechanism; C-Support; C1-Base plate; C2-Support plate; C3-Placement rack. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] In the description of the embodiments of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0055] A mild drying and calcination system for thin-walled hollow silica microspheres includes a drive mechanism 1, a transmission mechanism 2, a drum 3, a hot air generator 4, a hot air inlet pipe 5, a discharge pipe 6, a cyclone separator 7, a vibrating dispersion and sieving mechanism 8, and a calcination furnace A.

[0056] The drum 3 includes a cylinder body 31 and internal functional components 35. The cylinder body 31 has a feed inlet 32 ​​on its side wall, an air inlet 33 on its first end face, and a discharge outlet 34 on its second end face. At least one internal functional component 35 is arranged along the axial direction of the cylinder body 31. Figure 1 A schematic diagram shows a structure in which two internal functional components 35 are arranged along the axial direction of the cylinder 31. (Combined with...) Figure 1 and Figure 2 As shown, the internal functional component 35 includes a lifting plate 351, a support 352, and an air distribution plate 353. Multiple lifting plates 351 are arranged in a ring array around the axis of the cylinder 31 on the inner wall of the cylinder 31. Figure 2 A structural schematic diagram of eight lifting plates 351 is shown. To prevent material from being carried into the gaps of the lifting plates 351, the lifting plates 351 are designed as upright structures without tilt angles, that is, the central axis of the lifting plates 351 is parallel to the central axis of the cylinder 31.

[0057] The air distribution plate 353 is located at the center of the radial section of the cylinder 31, directly opposite the air inlet 33, and is used to disperse hot air into a uniform airflow. At least two supports 352 are included, with their first ends arranged in a ring array on the outer wall of the air distribution plate 353 and their second ends arranged on the inner wall of the cylinder 31. The supports 352 are used to fix and support the air distribution plate 353. Figure 2A schematic diagram of a structure including four supports 352 is shown. When there are eight lifting plates 351, the second ends of the four supports 352 are disposed on the inner side of the lifting plate 351 at the nearest corresponding position. Further, the cylinder 31 also includes a heat insulation layer 36. The heat insulation layer 36 is disposed between the lifting plates 351 and the inner wall of the cylinder 31. When the cylinder 31 also includes the heat insulation layer 36, the plurality of lifting plates 351 are arranged in a ring array around the axis of the cylinder 31 on the inner wall of the heat insulation layer 36.

[0058] The drive mechanism 1 is connected to the first end of the drum 3 via the transmission mechanism 2. The hot air generator 4 is connected to the air inlet 33 of the drum 3 via the hot air input pipe 5. The first end of the discharge pipe 6 is rotatably connected to the discharge port 34. Driven by the drive mechanism 1, the drum 3 rotates at a low speed relative to the discharge pipe 6. The drive mechanism 1 can be a variable frequency motor. The rotational power of the drum 3 is provided by the variable frequency motor through the transmission mechanism 2, realizing stepless adjustment of the speed.

[0059] The second end of the discharge pipe 6 is connected to the inlet of the cyclone separator 7. The outlet of the cyclone separator 7 is connected to the inlet of the vibrating dispersion and sieving mechanism 8. The inlet of the cyclone separator 7 is located at the top, and the outlet is located at the bottom. The outlet of the vibrating dispersion and sieving mechanism 8 is connected to the inlet of the screw conveyor 9. The vibrating dispersion and sieving mechanism 8, through the synergy of ultra-low mechanical energy and precise classification capabilities, solves the problem of dispersion damage and particle size control of fragile microspheres in the post-drying treatment stage, providing key technical support for obtaining highly intact, monodisperse hollow silica microspheres. Working in conjunction with the aforementioned roller 3, it fully embodies the process concept of "overcoming strength with softness," combining high efficiency and industrial feasibility.

[0060] The output port of the screw conveyor 9 is connected to the input port of the calcining furnace A. The screw conveyor 9 can achieve closed conveying. The calcining furnace A can achieve programmed temperature control.

[0061] The mild drying and calcination system for thin-walled hollow silica microspheres provided in this application embodiment involves the following steps: Upon system startup, the drive mechanism 1 is connected to the first end of the drum 3 via the transmission mechanism 2. The drive mechanism 1 drives the drum 3 to rotate at a low speed relative to the discharge pipe 6 via the transmission mechanism 2. The thin-walled hollow silica precursor slurry is fed in through the inlet 32 ​​located on the side wall of the drum 31. The lifting plates 351 in the annular array inside the drum repeatedly lift the slurry to a high position, after which it falls freely under gravity, forming a continuous thin-layer dynamic material curtain. This process completely avoids high-speed shear forces because the gravity dispersion force is far below the mechanical strength threshold of the wet gel, thus ensuring a significant reduction in damage to the fragile hollow structure during the drying, calcination, and dispersion stages. Simultaneously, the hot air generator 4 introduces low-temperature hot air (60°C~180°C) into the air inlet 33 of the drum 3 via the hot air input pipe 5. The hot air is evenly dispersed into a gentle airflow by the air distribution plate 353 located radially at the center of the drum 31, allowing for thorough and gentle heat exchange with the thin-layer dynamic material curtain, achieving low-temperature uniform mass transfer drying. This synergistic mechanism completely eliminates the local drying stress in thin-walled hollow silica precursor slurry caused by excessively high local wind speeds or uneven temperatures. Furthermore, because the material is continuously and dynamically updated, there is no opportunity for static bonding between particles, thus eliminating the formation of hard agglomerates at the source.

[0062] After drying, the precursor microspheres are carried by airflow from outlet 34 into outlet pipe 6, and then conveyed to cyclone separator 7 for gas-solid separation. The resulting solid microspheres then enter vibrating dispersion and sieving mechanism 8. Vibrating dispersion and sieving mechanism 8 uses gentle vibration at low frequency and low amplitude to dissolve soft agglomerates and simultaneously screen out broken particles, outputting monodisperse precursor microspheres. The monodisperse precursor microspheres are conveyed in a closed system by screw conveyor 9 to calcination furnace A, where they are calcined and solidified at a slow heating rate of 1℃ / min~5℃ / min. Throughout the process, the "gravity-driven dispersion + uniform airflow from air distribution plate 353" design of roller 3 replaces highly destructive atomization, the low-frequency gentle vibration of the vibrating screen avoids secondary structural damage, and the airtightness of screw conveyor 9 ensures pollution-free transmission, ultimately achieving a balance between the structural integrity and dispersibility of the microspheres. The integrity rate of hollow silica microspheres has been increased from less than 50% in traditional spray drying to over 95%.

[0063] This system achieves a balance between "gentle processing" and "continuous production" through the innovative integration of standardized industrial equipment. The drive mechanism 1, hot air generator 4, cyclone separator 7, screw conveyor 9, and calcining furnace A are all mature chemical equipment, significantly reducing the huge investment costs of specialized equipment (such as freeze dryers). The low-speed roller 3 and air distribution plate 353 work together to achieve low-energy dynamic drying, the low-frequency operation of the screen 82 reduces energy consumption, and the screw conveyor 9 ensures continuous, sealed transmission. This allows the system to be easily scaled up to ton-level capacity, possessing extremely high practicality and industrial value, and is readily achievable for large-scale industrial production.

[0064] Furthermore, the air distribution plate 353 has multiple through holes or parallel, elongated slits. During operation inside the drum 3, hot air enters through the air inlet 33 from the hot air input pipe 5. The air distribution plate 353 is located at the center of the radial section of the drum 31, directly opposite the air inlet 33, dispersing the hot air into a uniform airflow through the through holes or slits. This process ensures that the hot air and the thin-layer dynamic material curtain (formed by the thin-walled hollow silica precursor slurry under the action of the lifting plate 351) can fully and uniformly contact and transfer mass, avoiding thermal stress concentration caused by local wind speed or temperature differences. This significantly improves the uniformity and controllability of the drying process, preventing the thin-walled hollow silica precursor slurry from cracking due to localized overheating or excessively rapid drying, thereby protecting the integrity of the thin-walled hollow structure and improving product quality consistency.

[0065] The mild drying and calcination system for thin-walled hollow silica microspheres provided in this application embodiment also includes an exhaust gas treatment mechanism B. The exhaust gas treatment mechanism B is located at the top of the cyclone separator 7 and is used to treat and collect the separated exhaust gas. This exhaust gas treatment mechanism B can be a bag filter or a water film filter. During system operation, after the precursor microspheres received from the discharge pipe 6 by the cyclone separator 7 undergo gas-solid separation, the solid microspheres fall to the bottom, while the exhaust gas rises to the top. At this time, the exhaust gas treatment mechanism B (such as a bag filter or water film filter) treats and collects the exhaust gas, removing residual dust and recovering harmful substances, ensuring effective management of the separated exhaust gas. This reduces environmental pollution, improves the system's environmental friendliness, and reduces energy consumption and operating costs by recovering exhaust gas components (such as volatile organic compounds), enhancing the system's sustainability and industrial adaptability.

[0066] The vibration dispersion and sieving mechanism 8 provided in this embodiment includes a screen chamber 81, a screen 82, and a vibration mechanism. The inlet at the top of the screen chamber 81 is connected to the outlet of the cyclone separator 7. The screen 82 is mounted at the bottom. The vibration mechanism is connected to the screen 82 and is used to drive the screen 82 to vibrate. The inner cavity of the screen chamber 81 below the screen 82 is truncated. The outlet of the screen chamber 81 is connected to the inlet of the screw conveyor 9. In the system process, solid microspheres enter the top of the screen chamber 81 from the outlet of the cyclone separator 7. The vibration mechanism drives the screen 82 to vibrate gently with an adjustable low frequency and low amplitude. The screen 82 disperses and sieves the solid microspheres, dissolves soft agglomerates, and removes broken particles. Subsequently, the monodisperse precursor microspheres are collected through the truncated inner cavity at the bottom of the screen chamber 81 to the outlet and conveyed to the screw conveyor 9. This process enables continuous and dynamic microsphere processing, improving the dispersibility and uniformity of the microspheres and avoiding structural damage caused by subsequent mechanical crushing. At the same time, the use of a precision 82 sieve (200~2000 mesh) ensures a concentrated particle size distribution, improving product performance such as sphericity and strength, and meeting the needs of high-end applications.

[0067] The vibration dispersion sieving mechanism 8 provided in this embodiment also includes sound-insulating cotton 83. The sound-insulating cotton 83 is disposed on the outer wall of the sieve chamber 81 below the screen 82. Thus, when the vibration mechanism is working, the sound-insulating cotton 83 can absorb the noise and mechanical waves generated by the vibration, reducing noise propagation. This process works synergistically with the vibration of the screen 82 to ensure that the dispersion operation operates in a low-noise environment. This effectively reduces noise pollution at the work site (e.g., within the vibration frequency range of 15Hz~40Hz), improves the safety of the operating environment, and avoids secondary interference of noise on the microspheres, ensuring the stability of the dispersion process and improving the overall reliability and production efficiency of the system.

[0068] The components of the mild drying and calcination system for thin-walled hollow silica microspheres provided in this application embodiment are connected in one step along the material flow direction and work together.

[0069] Combination Figure 1 and Figure 2 As shown, the mild drying and calcination system for thin-walled hollow silica microspheres in this application embodiment also includes a support C, such as... Figure 1 As shown, the support C includes a base plate C1, a support plate C2, and a placement frame C3. A hot air generator 4 is mounted on the base plate C1. A hot air inlet pipe 5 and an outlet pipe 6 are respectively supported by the support plate C2, the bottom of which is mounted on the base plate C1. A drive mechanism 1 is mounted on the placement frame C3, which is also mounted on the base plate C1.

[0070] Another embodiment of the present invention provides a mild drying and calcination method for thin-walled hollow silica microspheres, comprising:

[0071] Step 1: A thin-walled hollow silica precursor slurry with a solid content of 5% to 25% is fed into the drum 3 through the feed port 32 provided on the side wall of the drum 31. The drum 3 rotates at a low speed relative to the discharge port 34 under the drive of the drive mechanism 1.

[0072] In step 1, the low-speed rotation of roller 3 is 5 rpm to 25 rpm. This rotation speed, in conjunction with the arrangement of the lifting plates 351, ensures that the shear force experienced by the thin-walled hollow silica precursor slurry during subsequent gravity dispersion is below the mechanical strength threshold of its gel network, thus preventing the hollow structure from breaking. This parameter range is crucial for ensuring the effectiveness of gravity dispersion and structural integrity. The low-speed rotation ensures that the impact force generated by the free fall of the slurry after being lifted by the lifting plates 351 is always below the mechanical strength threshold of the wet gel network (typically <10 kPa), preventing the microspheres from breaking during the dispersion stage. Simultaneously, this rotation speed, in conjunction with the angleless design of the lifting plates 351, allows the material to form a continuous and uniform thin-layer dynamic curtain to optimize heat exchange efficiency, while also preventing slurry residue in the gaps from causing uneven drying. The lower limit of the rotation speed (5 rpm) ensures that the material renewal frequency meets the needs of continuous production, while the upper limit (25 rpm) strictly limits the impact of centrifugal force on the fragile microspheres, providing structurally intact precursor microspheres for subsequent drying and calcination processes.

[0073] Step 2: Multiple lifting plates 351, arranged in a ring array around the axis of cylinder 31 on the inner wall of cylinder 31, repeatedly lift the thin-walled hollow silica precursor slurry to a certain height. Then, relying on gravity, the slurry is freely dropped, forming a uniform and continuous thin-layer dynamic material curtain. Simultaneously, a hot air generator 4 introduces low-temperature hot air (60℃~180℃) into the drum 3 through the hot air input pipe 5 and the air inlet 33. This low-temperature hot air is evenly distributed through the air distribution plate 353, located at the center of the radial section of cylinder 31 and directly opposite the air inlet 33, and then makes full and gentle contact with the thin-layer dynamic material curtain, allowing the moisture in the thin-walled hollow silica precursor slurry to gradually evaporate, resulting in dry precursor microspheres that maintain their structural integrity. Step 2 achieves gravity dispersion and low-temperature dynamic drying of the thin-walled hollow silica precursor slurry within the drum 3, which is crucial for protecting the fragile structure.

[0074] Steps 1 and 2 of this embodiment eliminate the intense shearing forces generated by high-speed rotation or high pressure. Utilizing the lifting action of the lifting plates 351 inside the low-speed rotating drum 3 (5 rpm ~ 25 rpm), the thin-walled hollow silica precursor slurry is raised to a certain height and then falls and disperses solely by its own gravity. This process is like a "sandfall," with gentle and controllable force. The resulting dispersion force is far lower than the mechanical strength of the wet gel hollow spheres, thus ensuring the integrity of the spheres. Simultaneously, the introduced low-temperature hot air (60℃ ~ 180℃), after being homogenized by the air distribution plate 353, fully contacts the continuously updated, curtain-like falling material, achieving uniform and slow drying in a dynamic process. This effectively eliminates localized drying stress and completely prevents the formation of hard agglomerates due to the continuous movement of the material.

[0075] Preferably, the temperature of the low-temperature hot air is 80℃~150℃.

[0076] In this embodiment, the thin-walled hollow silica precursor slurry is added first, and then the hot air generator 4 is turned on. The hot air heats up at a uniform speed, gradually heating the thin-walled hollow silica precursor slurry along with it, in order to prevent the surface of the thin-walled hollow silica precursor slurry from clumping. The discharge zone is directly cooled naturally, reducing energy consumption.

[0077] Step 3: The precursor microspheres are driven by airflow from the outlet 34 of the cylinder 31 to the outlet pipe 6, and then transported to the cyclone separator 7 through the outlet of the outlet pipe 6. In the cyclone separator 7, gas-solid separation is carried out to obtain solid microspheres. Most of the solid microspheres are efficiently separated and fall into the collection bin at the bottom of the cyclone separator 7.

[0078] Step 3 also includes treating and collecting the separated exhaust gas through the exhaust gas treatment mechanism B. Step 3 achieves the transportation and primary separation of the precursor microspheres. The exhaust gas treatment mechanism B (such as a bag / water film dust collector) at the top of the cyclone separator 7 achieves the dual goals of environmental protection and resource recovery. On the one hand, the dust-laden exhaust gas generated during the drying process is efficiently purified, with the dust emission concentration below 10mg / m³, avoiding air pollution. On the other hand, trace amounts of unseparated ultrafine powder (particle size <1μm) entrained in the exhaust gas are intercepted and recovered, which not only improves the utilization rate of raw materials but also prevents the loss of high-value-added nanoparticles, deeply integrating the cleanliness and economy of industrial production, and is especially suitable for the large-scale preparation of high-value materials.

[0079] Step 4: Solid microspheres are conveyed through the output port of cyclone separator 7 to vibrating dispersion and sieving mechanism 8. Under the adjustable low-frequency, low-amplitude vibration of vibrating dispersion and sieving mechanism 8, they are gently dispersed, soft agglomerates are broken, and broken particles and agglomerates that do not meet the particle size requirements are screened out. Well-dispersed monodisperse precursor microspheres are then output to the output port at the bottom of vibrating dispersion and sieving mechanism 8. Step 4 achieves gentle vibration dispersion and precise sieving of solid microspheres.

[0080] Step 4 specifically includes: solid microspheres are conveyed to the sieve chamber 81 through the output port of the cyclone separator 7. The vibration mechanism drives the screen 82 to vibrate at an adjustable low frequency and low amplitude, and the screen 82 gently disperses the solid microspheres to obtain monodisperse precursor microspheres. The monodisperse precursor microspheres are collected through the body-shaped inner cavity of the sieve chamber 81 and sent to the output port of the sieve chamber 81.

[0081] The vibrating dispersion sieving mechanism 8 solves the damage risk and grading problems in the post-processing of dried microspheres. The sieve 82, vibrating at low frequency (15Hz~40Hz) and low amplitude (0.5mm~2mm), applies only 0.1N / g~0.5N / g of mechanical energy, sufficient to dissolve hydrogen-bonded soft agglomerates, yet far below the microsphere breakage threshold (>2N / g), achieving "deagglomeration without breaking the spheres." The platform-shaped inner cavity design at the bottom of the sieve chamber 81 allows monodisperse microspheres to slide naturally to the output port by gravity, avoiding the introduction of secondary mechanical forces such as spiral pushing. This process is completed in a closed environment, isolating environmental pollutants from adsorption and controlling noise to <75dB through sound insulation cotton 83, forming a highly efficient, low-damage, and human-friendly industrial dispersion solution.

[0082] Furthermore, the vibration mechanism operates at a frequency of 15Hz to 40Hz and an amplitude of 0.5mm to 2mm. The mesh size of the 82-mesh sieve is selected based on the particle size (D50) of the target microspheres, ranging from 200 to 2000 mesh. Low-frequency, small-amplitude vibration ensures fewer mechanical impacts per unit time and lower energy per impact, maximizing the protection of the microsphere structure's integrity while disintegrating agglomerates. The 82-mesh sieve range covers particle size sorting requirements from 1μm to 75μm, allowing for flexible matching to different applications and high sieving accuracy. This parameter combination improves the particle size qualification rate and reduces the breakage rate, providing strictly compliant monodisperse products for high-end applications.

[0083] Step 5: The monodisperse precursor microspheres are conveyed to the screw conveyor 9 through the output port of the vibrating dispersion sieve mechanism 8, and then conveyed in a closed manner by the screw conveyor 9 to the programmable temperature controlled calcination furnace A. Under an air atmosphere, the temperature is slowly increased to 300℃~800℃ at a heating rate of 1℃ / min~5℃ / min for calcination, and held at this temperature for 1h~8h. This process completely removes the template agent and strengthens the wall structure, ultimately yielding hollow silica microspheres with thin walls, high strength, and good dispersibility. Step 5 enables programmable temperature controlled slow calcination.

[0084] The continuous post-processing of steps 3 to 5 involves the dried precursor microspheres being transported by airflow to the cyclone separator 7 for collection, followed by gentle dispersion and precise classification by the low-frequency, low-amplitude vibration dispersion and sieving mechanism 8. Finally, the microspheres are slowly calcined under programmed temperature control to steadily remove organic matter and densify the silica wall layer.

[0085] The mild drying and calcination method for thin-walled hollow silica microspheres provided in this application fundamentally solves three major challenges in industrial-scale preparation through a process chain design of "gravity dispersion + low-temperature dynamic drying + gentle post-treatment": The use of a low-speed roller 3 (5 rpm ~ 25 rpm) gravity dispersion mechanism replaces high-shear atomization, subjecting the wet gel microspheres to only gentle forces, avoiding structural breakage, and increasing the drying integrity rate to over 95%. The use of uniformly heated low-temperature hot air (60℃ ~ 180℃) from the air distribution plate 353 ensures full contact with the continuous thin-layer dynamic material curtain, eliminating localized drying stress and completely preventing hard agglomeration. Furthermore, the combined post-treatment of low-frequency vibration dispersion sieving and programmed slow calcination removes soft agglomerates while avoiding secondary damage, ensuring that the final product possesses both high dispersibility, a thin-walled structure free of microcracks, and excellent mechanical properties. This method achieves the unity of "gentle processing" and "continuous mass production" with conventional industrial equipment, significantly reducing equipment investment (only 1 / 5 to 1 / 3 of imported spray equipment), breaking through cost and scale bottlenecks. The resulting hollow silica microspheres have uniform wall thickness, dense skeleton, and perfect sphericity, and naturally possess excellent monodispersity without the need for post-depolymerization. The process has low energy consumption and can easily scale up production capacity, solving the global problem of industrial drying of fragile structural materials. It has extremely high economic promotion value and industrialization advantages.

[0086] To ensure that the above-described implementation details and operations of this application can be clearly understood by those skilled in the art, and to highlight the significant advancements of the mild drying and calcination system and method for thin-walled hollow silica microspheres in the embodiments of this application, the above technical solutions are illustrated below through multiple embodiments.

[0087] Example 1

[0088] A thin-walled hollow silica precursor slurry with a solid content of 5% was prepared (using the StöBer method combined with emulsion template).

[0089] Step 1: A thin-walled hollow silica precursor slurry with a solid content of 5% is pumped into the drum 3 through the feed port 32 set on the side wall of the drum 3 at a constant flow rate. The drum 3 is driven by the drive mechanism 1 and rotates at a low speed relative to the discharge port 34. The rotation speed is 5 rpm.

[0090] Step 2: The thin-walled hollow silica precursor slurry is repeatedly lifted to a certain height by multiple lifting plates 351 arranged in a ring array around the axis of the cylinder 31 on the inner wall of the cylinder 31. Then, the thin-walled hollow silica precursor slurry is freely sprinkled down by gravity to form a uniform and continuous thin-layer dynamic material curtain. At the same time, the hot air generator 4 gradually increases the temperature from 5℃ / min until low-temperature hot air at 60℃ is introduced into the drum 3 through the hot air input pipe 5 and the air inlet 33 of the drum 3. The low-temperature hot air is evenly distributed by the air distribution plate 353 set at the center of the radial section of the cylinder 31, directly opposite the air inlet 33, and then makes full and gentle countercurrent contact mass transfer with the thin-layer dynamic material curtain to obtain precursor microspheres.

[0091] Step 3: The precursor microspheres are driven by airflow from the outlet 34 of the cylinder 31 to the outlet pipe 6, and then transported to the cyclone separator 7 through the outlet of the outlet pipe 6. In the cyclone separator 7, gas-solid separation is carried out to obtain solid microspheres.

[0092] Step 4: Solid microspheres are conveyed to screen chamber 81 through the output port of cyclone separator 7. A vibration mechanism drives screen 82 to vibrate at a frequency of 15Hz and an amplitude of 0.5mm. Screen 82 (200 mesh) gently disperses the solid microspheres to obtain monodisperse precursor microspheres (with uniform particle size distribution). The monodisperse precursor microspheres are collected through the body-shaped inner cavity of screen chamber 81 and discharged to its output port.

[0093] Step 5: The monodisperse precursor microspheres are conveyed to the screw conveyor 9 through the output port of the vibrating dispersion sieve mechanism 8, and then conveyed to the muffle furnace in a closed manner through the screw conveyor 9. Under air atmosphere, the temperature is slowly increased to 300℃ at a heating rate of 1℃ / min for calcination, held at the temperature for 8 hours, and then cooled with the furnace to obtain hollow silica microspheres.

[0094] Example 2

[0095] A thin-walled hollow silica precursor slurry with a solid content of 15% was prepared (using the StöBer method combined with emulsion template).

[0096] Step 1: A thin-walled hollow silica precursor slurry with a solid content of 15% is pumped into the drum 3 through the feed port 32 set on the side wall of the drum 3 at a constant flow rate. The drum 3 is driven by the drive mechanism 1 and rotates at a low speed relative to the discharge port 34. The rotation speed is 12 rpm.

[0097] Step 2: The thin-walled hollow silica precursor slurry is repeatedly lifted to a certain height by multiple lifting plates 351 arranged in a ring array around the axis of the cylinder 31 on the inner wall of the cylinder 31. Then, the thin-walled hollow silica precursor slurry is freely sprinkled down by gravity, forming a uniform and continuous thin-layer dynamic material curtain. At the same time, the hot air generator 4 gradually increases the temperature from 5℃ / min until low-temperature hot air at 100℃ is introduced into the drum 3 through the hot air input pipe 5 and the air inlet 33 of the drum 3. The low-temperature hot air is evenly distributed by the air distribution plate 353 set at the center of the radial section of the cylinder 31, directly opposite the air inlet 33, and then makes full and gentle countercurrent contact mass transfer with the thin-layer dynamic material curtain to obtain precursor microspheres.

[0098] Step 3: The precursor microspheres are driven by airflow from the outlet 34 of the cylinder 31 to the outlet pipe 6, and then transported to the cyclone separator 7 through the outlet of the outlet pipe 6. In the cyclone separator 7, gas-solid separation is carried out to obtain solid microspheres.

[0099] Step 4: Solid microspheres are conveyed to screen chamber 81 through the output port of cyclone separator 7. A vibration mechanism drives screen 82 to vibrate at a frequency of 25Hz and an amplitude of 1.5mm. Screen 82 (2000 mesh) gently disperses the solid microspheres to obtain monodisperse precursor microspheres (monodisperse precursor microspheres have a uniform particle size distribution and a SPAN value < 1.5). The monodisperse precursor microspheres are collected through the body-shaped inner cavity of screen chamber 81 and discharged to the output port of screen chamber 81.

[0100] Step 5: The monodisperse precursor microspheres are conveyed to the screw conveyor 9 through the output port of the vibrating dispersion sieve mechanism 8, and then conveyed to the muffle furnace in a closed manner through the screw conveyor 9. Under air atmosphere, the temperature is slowly increased to 800℃ at a heating rate of 5℃ / min for calcination, held at the temperature for 4 hours, and then cooled with the furnace to obtain hollow silica microspheres.

[0101] The product obtained in Example 2 was observed by scanning electron microscopy (SEM) (e.g. Figure 3 As shown in the image, the particles are spherical and intact, with no visible breakage or collapse, exhibiting excellent dispersibility. Nitrogen adsorption tests show that they possess a typical mesoporous shell structure. Compressive strength simulation tests using a particle size analyzer revealed that their breakage pressure is significantly higher than that of similar spray-dried products on the market.

[0102] Example 3

[0103] A thin-walled hollow silica precursor slurry with a solid content of 25% was prepared (using the StöBer method combined with emulsion template).

[0104] Step 1: A thin-walled hollow silica precursor slurry with a solid content of 25% is pumped into the drum 3 through the feed port 32 set on the side wall of the drum 3 at a constant flow rate. The drum 3 is driven by the drive mechanism 1 and rotates at a low speed relative to the discharge port 34. The rotation speed is 25 rpm.

[0105] Step 2: The thin-walled hollow silica precursor slurry is repeatedly lifted to a certain height by multiple lifting plates 351 arranged in a ring array around the axis of the cylinder 31 on the inner wall of the cylinder 31. Then, the thin-walled hollow silica precursor slurry is freely sprinkled down by gravity to form a uniform and continuous thin-layer dynamic material curtain. At the same time, the hot air generator 4 gradually increases the temperature from 5℃ / min until low-temperature hot air at 180℃ is introduced into the drum 3 through the hot air input pipe 5 and the air inlet 33 of the drum 3. The low-temperature hot air is evenly distributed by the air distribution plate 353 set at the center of the radial section of the cylinder 31, directly opposite the air inlet 33, and then makes full and gentle countercurrent contact mass transfer with the thin-layer dynamic material curtain to obtain precursor microspheres.

[0106] Step 3: The precursor microspheres are driven by airflow from the outlet 34 of the cylinder 31 to the outlet pipe 6, and then transported to the cyclone separator 7 through the outlet of the outlet pipe 6. In the cyclone separator 7, gas-solid separation is carried out to obtain solid microspheres.

[0107] Step 4: Solid microspheres are conveyed to screen chamber 81 through the output port of cyclone separator 7. A vibration mechanism drives screen 82 to vibrate at a frequency of 40Hz and an amplitude of 2mm. Screen 82 (1100 mesh) gently disperses the solid microspheres to obtain monodisperse precursor microspheres (with uniform particle size distribution). The monodisperse precursor microspheres are collected through the body-shaped inner cavity of screen chamber 81 and discharged to its output port.

[0108] Step 5: The monodisperse precursor microspheres are conveyed to the screw conveyor 9 through the output port of the vibrating dispersion sieve mechanism 8, and then conveyed to the muffle furnace in a closed manner through the screw conveyor 9. Under air atmosphere, the temperature is slowly increased to 550°C at a heating rate of 5°C / min for calcination, held at 5°C for 1 hour, and then cooled with the furnace to obtain hollow silica microspheres.

[0109] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0110] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A mild drying and calcination system for thin-walled hollow silica microspheres, characterized in that, Includes a drive mechanism, transmission mechanism, drum, hot air generator, hot air inlet pipe, outlet pipe, cyclone separator, vibrating dispersion and screening mechanism, screw conveyor and calcining furnace; The drum includes a cylinder and internal functional components; The cylinder has a feed inlet on its side wall, an air inlet on its first end face, and a discharge outlet on its second end face. At least one of the internal functional components is provided along the axial direction of the cylinder; The built-in functional components include a reading board, a bracket, and a wind distribution plate; The lifting plates include multiple plates, which are arranged in a ring array around the axis of the cylinder on the inner wall of the cylinder. The air distribution plate is located at the center of the radial section of the cylinder, directly opposite the air inlet, and is used to disperse the hot air into a uniform airflow. The bracket includes at least two, with the first ends of the at least two brackets arranged in a ring array on the outer wall of the air distribution plate and the second ends arranged on the inner wall of the cylinder; The drive mechanism is connected to the first end of the drum via the transmission mechanism; The hot air generator is connected to the air inlet of the drum through the hot air input pipe; The first end of the discharge pipe is rotatably connected to the discharge port, and the roller rotates at a low speed relative to the discharge pipe under the drive of the drive mechanism. The second end of the discharge pipe is connected to the inlet of the cyclone separator; The output port of the cyclone separator is connected to the input port of the vibrating dispersion and screening mechanism; The output port of the vibrating dispersion screening mechanism is connected to the input port of the screw conveyor; The output port of the screw conveyor is connected to the input port of the calcining furnace.

2. The mild drying and calcination system for thin-walled hollow silica microspheres according to claim 1, characterized in that, The air distribution plate has multiple through holes evenly distributed, or the air distribution plate has multiple long and thin slits arranged in parallel.

3. The mild drying and calcination system for thin-walled hollow silica microspheres according to claim 1, characterized in that, It also includes an exhaust gas treatment system; The exhaust gas treatment mechanism is located on top of the cyclone separator.

4. The mild drying and calcination system for thin-walled hollow silica microspheres according to claim 1, characterized in that, The vibrating dispersion sieving mechanism includes a sieve chamber, a sieve screen, and a vibrating mechanism; The inlet at the top of the sieve chamber is connected to the outlet of the cyclone separator, and the sieve screen is installed at the bottom. The vibration mechanism is connected to the screen and is used to drive the screen to vibrate; The inner cavity of the sieve chamber located below the sieve mesh is truncated. The output port of the screen chamber is connected to the input port of the screw conveyor.

5. The mild drying and calcination system for thin-walled hollow silica microspheres according to claim 4, characterized in that, The vibration dispersion sieving mechanism also includes sound insulation cotton; The sound insulation cotton is disposed on the outer wall of the sieve chamber located below the sieve mesh.

6. A mild drying and calcination method for thin-walled hollow silica microspheres, characterized in that, The mild drying and calcination system based on any one of claims 1 to 5 for thin-walled hollow silica microspheres comprises: Step 1: A thin-walled hollow silica precursor slurry with a solid content of 5% to 25% is fed into the drum through a feed port provided on the side wall of the drum body. The drum rotates at a low speed relative to the discharge port under the drive mechanism. Step 2: The thin-walled hollow silica precursor slurry is repeatedly lifted to a certain height by multiple lifting plates arranged in a ring around the axis of the cylinder on the inner wall of the cylinder. Then, the thin-walled hollow silica precursor slurry is freely sprinkled by gravity to form a uniform and continuous thin-layer dynamic material curtain. At the same time, a hot air generator introduces low-temperature hot air at a temperature of 60℃~180℃ into the drum through a hot air input pipe and the air inlet of the drum. The low-temperature hot air is evenly distributed by an air distribution plate set at the center of the radial section of the cylinder and facing the air inlet. It then makes full and gentle contact mass transfer with the thin-layer dynamic material curtain to obtain precursor microspheres. Step 3: The precursor microspheres are driven by airflow from the outlet of the cylinder to the outlet pipe, and then transported to the cyclone separator through the outlet of the outlet pipe. In the cyclone separator, gas-solid separation is carried out to obtain solid microspheres. Step 4: The solid microspheres are conveyed to the vibration dispersion and sieving mechanism through the output port of the cyclone separator. They are gently dispersed under the adjustable low-frequency and low-amplitude vibration of the vibration dispersion and sieving mechanism to obtain monodisperse precursor microspheres, which are then output to the output port of the vibration dispersion and sieving mechanism. Step 5: The monodisperse precursor microspheres are conveyed to the screw conveyor through the output port of the vibrating dispersion sieving mechanism, and then conveyed to the calcining furnace through the screw conveyor in a closed manner. Under air atmosphere, the temperature is slowly increased to 300℃~800℃ at a heating rate of 1℃ / min~5℃ / min for calcination, and held for 1h~8h to obtain hollow silica microspheres.

7. The mild drying and calcination method for thin-walled hollow silica microspheres according to claim 6, characterized in that, The speed at which the drum rotates at low speed in step 1 is 5 rpm to 25 rpm.

8. The mild drying and calcination method for thin-walled hollow silica microspheres according to claim 6, characterized in that, Step 3 also includes processing and collecting the separated exhaust gas through an exhaust gas treatment device.

9. The mild drying and calcination method for thin-walled hollow silica microspheres according to claim 6, characterized in that, Step 4 specifically includes: the solid microspheres are conveyed to the sieve chamber through the output port of the cyclone separator; The vibration mechanism drives the screen to vibrate at an adjustable low frequency and low amplitude. The screen gently disperses the solid microspheres to obtain the monodisperse precursor microspheres. The monodisperse precursor microspheres are collected through the sieve chamber's platform-shaped inner cavity and then discharged to the sieve chamber's outlet.

10. The mild drying and calcination method for thin-walled hollow silica microspheres according to claim 9, characterized in that, The vibration frequency of the vibration mechanism is 15Hz~40Hz, the amplitude is 0.5mm~2mm, and the mesh size of the screen is 200 mesh~2000 mesh.

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